1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_T10_PI_H
3 #define _LINUX_T10_PI_H
4
5 #include <linux/types.h>
6 #include <linux/blk-mq.h>
7
8 /*
9 * A T10 PI-capable target device can be formatted with different
10 * protection schemes. Currently 0 through 3 are defined:
11 *
12 * Type 0 is regular (unprotected) I/O
13 *
14 * Type 1 defines the contents of the guard and reference tags
15 *
16 * Type 2 defines the contents of the guard and reference tags and
17 * uses 32-byte commands to seed the latter
18 *
19 * Type 3 defines the contents of the guard tag only
20 */
21 enum t10_dif_type {
22 T10_PI_TYPE0_PROTECTION = 0x0,
23 T10_PI_TYPE1_PROTECTION = 0x1,
24 T10_PI_TYPE2_PROTECTION = 0x2,
25 T10_PI_TYPE3_PROTECTION = 0x3,
26 };
27
28 /*
29 * T10 Protection Information tuple.
30 */
31 struct t10_pi_tuple {
32 __be16 guard_tag; /* Checksum */
33 __be16 app_tag; /* Opaque storage */
34 __be32 ref_tag; /* Target LBA or indirect LBA */
35 };
36
37 #define T10_PI_APP_ESCAPE cpu_to_be16(0xffff)
38 #define T10_PI_REF_ESCAPE cpu_to_be32(0xffffffff)
39
40 static inline u32 t10_pi_ref_tag(struct request *rq)
41 {
42 unsigned int shift = ilog2(queue_logical_block_size(rq->q));
43
44 if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
45 rq->q->limits.integrity.interval_exp)
46 shift = rq->q->limits.integrity.interval_exp;
47 return blk_rq_pos(rq) >> (shift - SECTOR_SHIFT) & 0xffffffff;
48 }
49
50 struct crc64_pi_tuple {
51 __be64 guard_tag;
52 __be16 app_tag;
53 __u8 ref_tag[6];
54 };
55
56 /**
57 * lower_48_bits() - return bits 0-47 of a number
58 * @n: the number we're accessing
59 */
60 static inline u64 lower_48_bits(u64 n)
61 {
62 return n & ((1ull << 48) - 1);
63 }
64
65 static inline u64 ext_pi_ref_tag(struct request *rq)
66 {
67 unsigned int shift = ilog2(queue_logical_block_size(rq->q));
68
69 if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
70 rq->q->limits.integrity.interval_exp)
71 shift = rq->q->limits.integrity.interval_exp;
72 return lower_48_bits(blk_rq_pos(rq) >> (shift - SECTOR_SHIFT));
73 }
74
75 #endif
76
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.